p-Toluenesulfonic acid → Methyl alpha-[6-methyl-4-(3-phenylphenoxy)-5-pyrimidinyl]-beta-methoxyacrylate

Participants

Reaction Steps

Methyl α-[6-methyl-4-(3-phenylphenoxy)-5-pyrimidinyl]-β-dimethylaminoacrylate (60 g, 0.15 mol) is dissolved in diethylether (300 ml) and a solution of p-toluene sulfonic acid (44 g, 0.23 mol) in water (200 ml) is added at room temperature with stirring. After 16 hours the mixture is partially neutralized by adding solid potassium bicarbonate (28 g). Extraction of the product with diethylether, drying of the organic phase (MgSO4) and evaporation of the solvent gives the crude enol (52 g, 93%). The product is dissolved in dimethylformamide (100 ml) and potassium carbonate (33 g, 0.24 mol) and dimethyl sulfate (18.9 g, 0.15 mol) is added with cooling. After stirring the reaction mixture at room temperature for 3 hours, diethylether is added and the mixture is washed repeatedly with bring. Drying and chromatography on silicagel (eluant: hexane/ethyl acetate 1:1) gives the pure methyl α-[6-methyl-4(3-phenylphenoxy)-5-pyrimidinyl]-β-methoxyacrylate as a yellowish oil (46 g, 85%).

Provenance & Evidence